At first I loved it because it made swimming to shore less painful. But despite that it actually breaks several things in my opinion.
A: It is way too silent. This makes it too easy to sneak up on people/ships super fast in an unintended way.
B: It makes boarding way too easy both due to moving faster than a full wind Galeon and being silent. Makes it hard for solo or duo crews to stand a chance when they can get easily boarded and killed or distracted while a Galeon is still firing on them.
C: Makes launching yourself out of a cannon nearly obsolete. This fun mechanic that was suppose to be the risk reward way of boarding an enemy ship is almost never used. It is easier to accurately, easily, swiftly and silently sword dash through the water.
D: It speeds up processes that were suppose to be slow or risky.
The actual solution is to add a better way to get to shore and back, especially from the large boat. One that doesn't break immersion and physics.
At the moment I completely avoid PvP despite enjoying the sea battles. Because every sea battle is instant boarding then blunderbus one shotting. Especially when sailing with 1-2 people vs 3-4 people. It only takes one boarder to disrupt the entire operation of a ship, which is fine, if they earned getting on your ship through legitimate means such as... the cannons, ramming, sailing beside/by your ship, stealth, risking sharks and swimming. I feel it should not be removed, but that the water should drastically dampen the momentum compared to what it currently does.
I never really experience fun cannon battles or high risk ship maneuvers. Almost every PvP fight is just a couple shots fired, then people start sword dashing.
EDIT: For those who don't believe it was a community discovered bug.
https://www.reddit.com/r/xboxone/comments/84vzkj/its_rare_ltd_developers_of_sea_of_thieves_ask/dvsu0p7/?context=3 Credit finding this to @Raigagogyou
There is a dev video too where it is mentioned, still looking for that.